RAVE J203843.2-002333: The First Highly R-process-enhanced Star Identified in the RAVE Survey

• Main Authors: Placco, Vinicius M. (Author), Holmbeck, Erika M. (Author), Beers, Timothy C. (Author), Surman, Rebecca A. (Author), Points, Sean D. (Author), Kaleida, Catherine C. (Author), Hansen, Terese T. (Author), Sakari, Charli M. (Author), Casey, Andrew R. (Author), Frebel, Anna L. (Contributor), Ji, Alexander Pung (Contributor), Ezzeddine, Rana (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Physics (Contributor), MIT Kavli Institute for Astrophysics and Space Research (Contributor)
• Format: Article
• Language: English
• Published: IOP Publishing, 2017-11-28T15:54:30Z.
• Subjects: Article
• Online Access: Get fulltext

We report the discovery of RAVE J203843.2-002333, a bright (V = 12.73), very metal-poor ([Fe/H] = -2.91), r-process-enhanced ([Ba/Eu] = +1.64 and = -0.81) star selected from the RAVE survey. This star was identified as a metal-poor candidate based on its medium-resolution (R ∼ 1600) spectrum obtained with the KPNO/Mayall Telescope, and followed up with high-resolution (R ∼ 66,000) spectroscopy with the Magellan/Clay Telescope, allowing for the determination of elemental abundances for 24 neutron-capture elements, including thorium and uranium. RAVE J2038-0023 is only the fourth metal-poor star with a clearly measured U abundance. The derived chemical abundance pattern exhibits good agreement with those of other known highly r-process-enhanced stars, and evidence suggests that it is not an actinide-boost star. Age estimates were calculated using U/X abundance ratios, yielding a mean age of 13.0 ± 1.1 Gyr.
National Science Foundation (U.S.) (CAREER Grant AST-1255160)
National Science Foundation (U.S.). Physics Frontier Center/Joint Institute for Nuclear Astrophysics (PHY 14-30152)
National Science Foundation (U.S.). Physics Frontier Center/JINA Center for the Evolution of the Elements